In its place, though, there’s a new problem: USB power.
On some desktop PCs, even when they’re turned off, you can charge your smartphone via a USB socket.
It turns out there’s a method to all this madness — but first we have to explain how USB power actually works.
There are now four USB specifications — USB 1.0, 2.0, 3.0, and 3.1 — in addition to the new USB-C connector.
We’ll point out where they significantly differ, but for the most part, we’ll focus on USB 3.0, as it’s the most common.
The tech world has finally coalesced around a charging standard, after years of proprietary adapters and ugly wall-wart power supplies.
Well, sort of: We’re already seeing some fragmentation in terms of the new USB-C connector, which could eventually replace USB, as well as what is thankfully turning out to be a short-lived obsession Samsung had with larger USB micro-B connectors for its Galaxy line.
But aside from that, and with the obvious exception of Apple’s Lightning connector, micro USB has destroyed the industry’s penchant for custom ports.
Ten years ago, you always had to make sure you had the correct power supply for each of your gadgets. Today, you can charge your phone at your friend’s house, plug your ebook reader into any computer, and download photos from a digital camera directly to your TV, all thanks to a standardized connector.
In a USB network, there is one host and one device.
In almost every case, your PC is the host, and your smartphone, tablet, or camera is the device.
Power always flows from the host to the device, although data can flow in both directions, such as when you copy files back and forth between your computer and your phone. A regular USB 1.0 or 2.0 socket has four pins, and a USB cable has four wires.